June is Cancer Immunotherapy Month. Why boosting the immune system is the new big thing in cancer research.
Immunotherapy is, much like it sounds, cancer treatment that utilizes the body’s immune system. Also known as virutherapy, the idea behind this type of treatment is getting the body’s own system to attack cancer cells and, ideally, leave normal tissues unharmed.
Immunotherapy was first used in 1891 by New York surgeon, Dr. William Coley. Bacteria were injected into cancerous tumors with the goal of prompting an immune response to the infection that would attack the tumor.
The immune system produces T cells which track down and eliminate problematic cells. But cancer cells are masters of defense, expressing proteins that suppress T cells around a tumor. The immune system doesn’t recognize the tumor as being harmful and leaves it alone. Efforts to create a vaccine that would warn the immune system of cancerous changes have failed, but the race to create advanced immunotherapy treatment is in full swing.
Earlier this year the FDA approved the use of another drug, Opdivo (nivolumab), to treat advanced squamous non-small cell lung cancer. The drug was approved last fall for the treatment of melanoma that is either in advanced stages or inoperable. Opdivo blocks the protein that normally suppresses T cells, making cancerous cells detectable by the immune system.
So far it appears immunotherapy is effective for several types of cancers, including certain lung cancers, melanoma, kidney and bladder cancer, lymphoma, and possibly breast cancer. The therapy does have its drawbacks. The immune system can attack healthy cells, causing serious side effects and even immune-related death, though this is rare.
Common side effects of immunotherapy drugs are fatigue and rash. Much less severe than those of chemotherapy. While long term data is a ways off, survival rates of 3+ years have been reported in lung cancer patients, longer in melanoma. It appears that T cells seem to remember how to defend the body against cancer even after the therapy has stopped.
Because every body and immune system is different, doctors are researching ways to personalize immunotherapy treatments to each patient. Of course, the biggest drawback right now with the use of these new therapies is cost. $12,000 for one round is raising many eyebrows, but candidates may be placed on a patient assistance program.
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